VERB (3)

1. ask humbly (for something);
- Example: "He supplicated the King for clemency"

2. make a humble, earnest petition;
- Example: "supplicate for permission"

3. ask for humbly or earnestly, as in prayer;
- Example: "supplicate God's blessing"

The Collaborative International Dictionary of English v.0.48:

Supplicate \Sup"pli*cate\, v. t. [imp. & p. p. Supplicated; p.
   pr. & vb. n. Supplicating.] [L. supplicatus, p. p. of
   supplicare to supplicate; of uncertain origin, cf. supplex,
   supplicis, humbly begging or entreating; perhaps fr. sub
   under + a word akin to placare to reconcile, appease (cf.
   Placable), or fr. sub under + plicare to fold, whence the
   idea of bending the knees (cf. Ply, v. t.). Cf. Supple.]
   1. To entreat for; to seek by earnest prayer; to ask for
      earnestly and humbly; as, to supplicate blessings on
      Christian efforts to spread the gospel.
      [1913 Webster]

   2. To address in prayer; to entreat as a supplicant; as, to
      supplicate the Deity.
      [1913 Webster]

   Syn: To beseech; entreat; beg; petition; implore; importune;
        solicit; crave. See Beseech.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Supplicate \Sup"pli*cate\, v. i.
   To make petition with earnestness and submission; to implore.
   [1913 Webster]

         A man can not brook to supplicate or beg. --Bacon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

supplicate
    v 1: ask humbly (for something); "He supplicated the King for
         clemency"
    2: make a humble, earnest petition; "supplicate for permission"
    3: ask for humbly or earnestly, as in prayer; "supplicate God's
       blessing"

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "supplicate":
   adjure, appeal, appeal to, beg, beseech, call for help, call on,
   call upon, clamor for, commune with God, conjure, crave, cry for,
   cry on, cry to, entreat, give thanks, impetrate, implore,
   importune, imprecate, invoke, kneel to, make supplication, obtest,
   offer a prayer, petition, plead, plead for, pray, pray over,
   recite the rosary, return thanks, run to, say grace